<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style type="text/css">
	#box1 { width: 300px; height: 300px; background: blueviolet; }
	#box2 { width: 200px; height: 200px; background: aquamarine; }
	#box3 { width: 100px; height: 100px; background: tomato; }
	div { overflow: hidden; margin: 50px auto; }
</style>
</head>
<body>
<div id="box1">
	<div id="box2">
    	<div id="box3"></div>
    </div>
</div>

<script type="text/javascript" src="eventTest.js"></script>
</body>
</html>